2006 INFINITI QX56 sensor

TROUBLE DIAGNOSISATC-65
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Revision: November 2009 2006 QX56
SYSTEM DESCRIPTION
Component Parts
Mode door control system components are:

Front air control

Mode door motor

PBR (built into mode door motor)

In-vehicle sensor

Ambient sensor

Optical sensor

Intake sensor
System Operation
The mode door position (vent, B/L, foot, and defrost) is set by the front air control by means of the mode door
motor. When a mode door position is selected on the front air control, voltage is applied to one circuit of the
mode door motor while ground is applied to the other circuit, causing the mode door motor to rotate. The direc-
tion of rotation is determined by which circuit has voltage applied to it, and which one has ground applied to it.
The front air control monitors the mode door position by measuring the voltage signal on the PBR circuit.
In AUTO mode the mode door position is set by the front air control which determines the proper position
based on inputs from the in-vehicle sensor, ambient sensor, optical sensor, intake sensor, and the temperature
selected by the driver or passenger.
Mode Door Control Specification
WJIA1240E
WJIA0434E

TROUBLE DIAGNOSISATC-71
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Revision: November 2009 2006 QX56
SYSTEM DESCRIPTION
Component Parts
Air mix door control system components are:

Front air control.

Air mix door motors (Driver, Passenger, and rear)

PBR (built-into air mix door motors)

In-vehicle sensor

Ambient sensor

Optical sensor

Intake sensor
System Operation
The front air control receives data from the temperature selected by the driver side, passenger side, and rear.
The front air control then applies a voltage to one circuit of the appropriate air mix door motor, while ground is
applied to the other circuit, causing the appropriate air mix door motor to rotate. The direction of rotation is
determined by which circuit has voltage applied to it, and which one has ground applied to it. The front air con-
trol monitors the air mix door positions by measuring the voltage signal on the PBR circuits of each door.
In AUTO mode the air mix, intake, mode door, and defrost door positions are set by the front air control which
determines the proper position based on inputs from the in-vehicle sensor, ambient sensor, optical sensor,
intake sensor, and the temperature selected by the driver and front and rear passengers.
Subsequently, HOT/COLD or DEFROST/VENT or FRESH/RECIRCULATION operation is selected. The new
door position data is returned to the front air control.
Air Mix Door Control Specification
WJIA1244E
WJIA0435E

ATC-84
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
SYSTEM DESCRIPTION
Component Parts
Intake door control system components are:

Front air control

Intake door motor

In-vehicle sensor

Ambient sensor

Optical sensor

Intake sensor
System Operation
The intake door control determines the intake door position based on the position of the recirculation switch.
When the recirculation switch is depressed the intake door motor rotates closing off the fresh air inlet and
recirculating the cabin air. If the recirculation switch is depressed again, the intake door motor rotates in the
opposite direction, again allowing fresh air into the cabin.
In the AUTO mode, the front air control determines the intake door position based on the ambient tempera-
ture, the intake air temperature and the in-vehicle temperature. When the DEF, D/F, FLOOR or OFF switches
are pushed, the front air control sets the intake door at the fresh position.
Intake Door Control Specification
WJIA1915E
WJIA0436E

ATC-88
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
SYSTEM DESCRIPTION
Component Parts
Defroster door control system components are:

Front air control

Defroster door motor

PBR (Built into defroster door motor)

In-vehicle sensor

Ambient sensor

Optical sensor

Intake sensor
System Operation
The front air control determines defroster door position based on the position of the defroster switch. When the
defroster switch is depressed, the defroster door motor rotates directing air to the defroster ducts. When any
mode other than defroster is selected, the defroster motor rotates in the opposite direction closing off air flow
to the defroster ducts.
In the AUTO mode, the front air control determines defroster door position based on the ambient temperature,
the intake air temperature and the in-vehicle temperature.
COMPONENT DESCRIPTION
Defroster door motor
The defroster door motor is attached to the front heater & cooling
unit assembly. The front air control sends a voltage to rotate to the
defroster door directing the air flow either to the defroster ducts, or to
the floor ducts, depending on which way the voltage and ground are
applied to the motor leads. Motor rotation is conveyed to a lever
which activates the defroster door.
WJIA1354E
WJIA0592E

TROUBLE DIAGNOSISATC-93
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Revision: November 2009 2006 QX56
Front Blower Motor CircuitEJS003XS
SYMPTOM:

Blower motor operation is malfunctioning.
INSPECTION FLOW
*1 .AT C - 5 8 , "Operational Check
(Front)"
*2AT C - 5 6 , "A/C System Self-diagnosis
Function"
*3ATC-57, "SELF-DIAGNOSIS CODE
CHART"
*4 ATC-95, "DIAGNOSTIC PROCE-
DURE FOR BLOWER MOTOR"
*5EC-192, "DTC P0117, P0118 ECT
SENSOR"
*6ATC-39, "SYMPTOM TABLE"
WJIA1251E

ATC-94
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
SYSTEM DESCRIPTION
Component Parts
Blower speed control system components are:

Front air control

Variable blower control

Front blower motor relay

Front blower motor

In-vehicle sensor

Ambient sensor

Optical sensor

Intake sensor
System Operation
Automatic Mode
In the automatic mode, the blower motor speed is calculated by the front air control and variable blower control
based on input from the in-vehicle sensor, optical sensor, intake sensor and ambient sensor, and potentio tem-
perature control (PTC).
When the air flow is increased, the blower motor speed is adjusted gradually to prevent a sudden increase in
air flow.
In addition to manual air flow control and the usual automatic air flow control, starting air flow control, low
water temperature starting control and high passenger compartment temperature starting control are avail-
able.
Starting Blower Speed Control
Start up from cold soak condition (Automatic mode).
In a cold start up condition where the engine coolant temperature is below 50°C (122 °F), the blower will not
operate at blower speed 1 for a short period of time (up to 210 seconds). The exact start delay time varies
depending on the ambient and engine coolant temperatures.
In the most extreme case (very low ambient temperature) the blower starting delay will be 210 seconds as
described above. After the coolant temperature reaches 50 °C (122 °F), or the 210 seconds has elapsed, the
blower speed will increase to the objective blower speed.
Start up from usual operating or hot soak condition (Automatic mode).
The blower will begin operation momentarily after the AUTO switch is pushed. The blower speed will gradually
rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective
blower speed).
WJIA1357E

TROUBLE DIAGNOSISATC-115
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Revision: November 2009 2006 QX56
Magnet Clutch CircuitEJS003XV
SYMPTOM: Magnet clutch does not engage.
INSPECTION FLOW
*1 .ATC-58, "Operational Check
(Front)"
*2ATC-56, "A/C System Self-diagnosis
Function"
*3 AT C - 5 7 , "SELF-DIAGNOSIS CODE
CHART"
*4ATC-134, "Ambient Sensor Circuit"*5ATC-142, "Intake Sensor Circuit"
WJIA1285E

ATC-116
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
SYSTEM DESCRIPTION
The front air control controls compressor operation based on ambient and intake temperature and a signal
from ECM.
Low Temperature Protection Control
The front air control will turn the compressor ON or OFF as determined by a signal detected by the intake sen-
sor and the ambient sensor.
When intake air temperature is higher than the preset value, the compressor turns ON. The compressor turns
OFF when intake air temperature is lower than the preset value. That preset value is dependent on the ambi-
ent temperature, refer to the following table.
DIAGNOSTIC PROCEDURE FOR MAGNET CLUTCH
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
1. CHECK INTAKE AND AMBIENT SENSOR CIRCUITS
Check intake and ambient sensors. Refer to AT C - 5 6 , "
A/C System Self-diagnosis Function" .
OK or NG
OK >> GO TO 2.
NG >>

Malfunctioning intake sensor. Refer to ATC-142, "Intake Sensor Circuit" .

Malfunctioning ambient sensor. Refer to ATC-142, "Intake Sensor Circuit" .
Ambient temperature °C (°F)C om pr esso r ON
intake temperature °C ( °F)C o m p r e s s o r O F F
intake temperature ° C (°F)
0 (32) 2.5 (37) 2.0 (36)
10 (50) 2.5 (37) 2.0 (36)
20 (68) 2.5 (37) 1.5 (35)
30 (86) 2.0 (36) 0.5 (33)
40 (104) 2.0 (36)0.5 (33)
50 (122) 2.0 (36)0.5 (33)
WJIA1369E